Select the correct answer. Along with Earth's crust, which portion of the upper mantle forms the lithosphere? A. cooler, more rigid outer portion B. hotter, liquid-like inner portion C. cooler, liquid-like inner portion D. hotter, more rigid outer portion Reset

The portion of the upper mantle that, along with Earth's crust, forms the lithosphere is the cooler, more rigid outer portion. This is because the lithosphere comprises the crust and the uppermost solid part of the mantle, which is characterized by its strength and ability to support tectonic plates. The lithosphere is instrumental in tectonic activities, such as earthquakes and volcanic eruptions, as the plates move and interact along their boundaries – leading to the dynamic nature of our planet's surface. This fascinating interplay continues to shape landscapes over geological time scales!